1. Human Reproduction

Category Archives: Human Reproduction

Vitrification of Oocytes & Embryos by Suzanne Cawood Part 2 – Video

Posted on by


Vitrification of Oocytes Embryos by Suzanne Cawood Part 2
This lecture was part of the scientific program of IVF Lite 2011, which was held in August 2011 at Radisson Blu Resort, Goa. The landmark conference was sponsored by the IVF Lite Foundation...

By: IVF Lite Foundation

Read the original here:
Vitrification of Oocytes & Embryos by Suzanne Cawood Part 2 - Video

Keep calm and… stop? Fertility treatment in a pandemic – BioNews

Posted on by

16 March 2020

The spread of a novel coronavirus (SARS-CoV-2), which causes the disease COVID-19, presents UK fertility clinics and patients with a unique set of challenges. Some of this is because we simply don't know enough about the effects of the infection on fertility, fertility treatment and early pregnancy. Early data, summarised in the Royal College of Obstetricians and Gynaecologists guidance, are reassuring, but the number of reported cases is still small.

Clinics could face logistical challenges if large numbers of staff are unable to work due to quarantine requirements, or if elective work in hospitals is shut down to make space for emergencies. Should this prospect impact the advice we give patients? The UK Government, at the time of writing, has held back from the more radical social distancing measures implemented in other countries. This leaves clinics with a dilemma of whether to continue to offer fertility treatment to unaffected patients, or to go beyond current Government advice and suspend services.

Patients' anxieties are understandable and those who wish to delay their treatment should be accommodated. It makes sense for anyone who meets the criteria for self-isolation (which are also evolving as we write) to be advised not to start treatment and indeed to stop active treatment if already commenced.

Some would go further and say that all elective fertility treatment should be delayed. The European Society forHuman Reproduction and Embryology advises that all fertility patients should 'avoid becoming pregnant at this time'. A Twitter poll targeting reproductive medicine clinicians found 45.5 percent support for delaying frozen embryo replacement in patients in areas with a high COVID-19 burden.

The question then arises, for how long should treatment be delayed? It is reported that the UK will see the peak of infections three months from now, with a tail persisting into the autumn and a potential second peak after this. If we were to delay all fertility treatment, UK clinics may struggle with the capacity to cope with demand when treatments re-start. One could easily envisage a delay of six months, which may well harm the chances of conception for some patients. Hence the need for advice to be tailored to each individual patient's situation. Delaying treatment, in effect closing clinics, would have other impacts including financial strain (particularly for smaller stand-alone clinics) and loss of morale among the more vulnerable fertility patients.

Furthermore, Chinese researchers have identified that testicular Leydig cells and seminiferous tubules express the angiotensin-converting enzyme 2 (ACE2) receptor, which is used by the virus to gain entry into cells. This short discussion paper has not been peer-reviewed and there is no evidence to suggest that the virus is found in the testes, as reported in BioNews 1039. However, this paper does alert to the need for further research into whether male fertility may be affected by COVID-19, so that patients can be adequately counselled.

The fact is that this is a fast-moving situation, with facts and knowledge changing daily. This makes it hard for professional bodies to issue meaningful guidance to practitioners and patients. The American Society for Reproductive Medicine even calls its guidance 'suggestions', showing the tentative nature of such advice. As far as UK clinics are concerned, unless restriction of movement is introduced, it is reasonable to continue treatment for those who are well and wish to continue. However, centres must be prepared to terminate or complete treatment (including through cycle cancellation, oocyte or embryo freezing) and cease initiating new treatments as and when 'lock-down' commences.

Clinicians have in their toolbox measures, which can be taken proactively, to reduce the risk to patients who find themselves in a situation where treatment has to stop. A patient may develop symptoms, or fall into a risk group, for COVID-19 after having started ovarian stimulation. Patients on a g onadotropin-releasing hormone (GnRH) antagonist regime could be managed by stopping follicle-stimulating hormone (FSH) administration and continuing antagonist administration until the patient's ovarian response has settled. Data from small case studies indicate that GnRH antagonist continuation after the trigger of final oocyte maturation is effective in reducing the risk of ovarian hyperstimulation syndrome (OHSS). Where concern exists about a high ovarian reserve, consideration should be given to co-treatment with letrozole, keeping oestradiol levels low and reducing concern about the risk of OHSS.

The key is anticipation of problems, both clinical and organisational. All centres should have a contingency plan in place that describes a stepwise reduction in their activities. This allows prioritisation down to a minimal activity if needed. It is unlikely that any licensed fertility clinic can shut down completely; work goes on behind the scenes, in particular around the maintenance of storage banks. There are practical considerations for this maintaining tanks for example but also the regulatory issues around consent expiry and data management. Urgent medical issues will still arise, and it may be appropriate to maintain a fertility preservation service for cancer patients. This prioritisation must take into account national and local pandemic policies, as well as recognition of likely reduced levels of staffing due to illness and isolation. Mitigation policies may include replacing consultations with phone- or video-calls and making sure there is a good communication policy for patients who have treatment-related problems.

We must also bear in mind the anxiety that is generated by how this pandemic is playing out. In our connected world, news, including fake news, travels faster than the virus. It is hard to escape the sense of a storm looming or a tidal wave about to break. In some countries, of course, the storm is now raging and the tide has overwhelmed even well-resourced health systems.

Fittingly for the first pandemic of the social media age, there have been extensive informal discussions on these issues among clinicians across many social media platforms. US colleagues have collated a number of measures, gleaned from social media, that clinics should consider in their response to this challenge.

Things are moving apace, and we must respond in a safe and effective way, but without panic. The British Fertility Society and the Association of Reproductive Clinical Scientists are committed to providing guidance to UK clinics as the situation evolves.

Read more here:
Keep calm and... stop? Fertility treatment in a pandemic - BioNews

human reproduction – eschooltoday

Posted on by

Introduction to sexual reproduction Almost every growing up person has wondered where babies come from. If you are learning with us today, then you are probably a grown up kid and hopefully, you shall understand this bundle of excitement, and you shall learn to be more responsible in your boy-girl activities.

Reproduction generally means the action or process of making a copy of something. Human reproduction, specifically, is a wonderful, natural instance of humans making new humans (offspring) or giving birth to new humans (babies).

Reproduction is necessary for continuity of humans. This means without it, humans will no longer exist, as there will be no replacement when we grow very old and die.

There are two types of reproduction in living things

involves two individuals of the same species, usually a male and female. Asexual reproduction can occur without the involvement of another, and this is usually found in single cell organisms and in some plants.

As children grow up to become adults, their brains work with their reproductive organs to get them ready reproduce. This sexual development process takes time and it is called puberty. To understand this lesson, make sure to read about these: (Puberty For Boys, Puberty for Girls and Menstruation)

Let us start by looking at the female reproductive organ.

Read more:
human reproduction - eschooltoday

Rotunda – The Center for Human Reproduction

Posted on by

Welcome to Rotunda The Center for Human Reproduction Our website is a place where you can learn about the services and staff at Rotunda.

We know that facing infertility can be one of the most stressful situations you may encounter, emotionally, physically and sometimes financially. At Rotunda, we work hand-in-hand with you to make every phase of the process from diagnosis to treatment as predictable and comfortable as possible. Together we will map out a plan to determine the cause of your infertility and an appropriate course of action. Many problems can easily be corrected with medication or surgical procedures. For couples facing more difficult challenges, our ART program ranks amongst the best in the nation.

We know that when you visit an infertility clinic you may be worried about a procedure, a result, or your next step. Our staff is here to answer all your questions, offer support, and make any procedure as comfortable as possible. Our goal is to provide our patients with state-of-the-art medical care and an environment that fosters the best possible outcome.

See the original post here:
Rotunda - The Center for Human Reproduction

Reproductive system – Wikipedia

Posted on by

The reproductive system or genital system is a system of sex organs within an organism which work together for the purpose of sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system.[1] Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.[2]

In mammals, the major organs of the reproductive system include the external genitalia (penis and vulva) as well as a number of internal organs including the gamete producing gonads (testicles and ovaries). Diseases of the human reproductive system are very common and widespread, particularly communicable sexually transmitted diseases.[3]

Most other vertebrate animals have generally similar reproductive systems consisting of gonads, ducts, and openings. However, there is a great diversity of physical adaptations as well as reproductive strategies in every group of vertebrates.

Vertebrate animals all share key elements of their reproductive systems. They all have gamete-producing organs or gonads. In females, these gonads are then connected by oviducts to an opening to the outside of the body, typically the cloaca, but sometimes to a unique pore such as a vagina or intromittent organ.

The human reproductive system usually involves internal fertilization by sexual intercourse. During this process, the male inserts his erect penis into the female's vagina and ejaculates semen, which contains sperm. The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum. Upon successful fertilization and implantation, gestation of the fetus then occurs within the female's uterus for approximately nine months, this process is known as pregnancy in humans. Gestation ends with birth, the process of birth is known as labor. Labor consists of the muscles of the uterus contracting, the cervix dilating, and the baby passing out the vagina (the female genital organ). Human's babies and children are nearly helpless and require high levels of parental care for many years. One important type of parental care is the use of the mammary glands in the female breasts to nurse the baby.[4]

The female reproductive system has two functions: The first is to produce egg cells, and the second is to protect and nourish the offspring until birth. The male reproductive system has one function, and it is to produce and deposit sperm. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, numerous differences typically occur in secondary sexual characteristics.

The male reproductive system is a series of organs located outside of the body and around the pelvis region of a male that contribute towards the reproduction process. The primary direct function of the male reproductive system is to provide the male sperm for fertilization of the ovum.

The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place in the testes which are housed in the temperature regulating scrotum, immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the seminal vesicles, prostate, and the vas deferens. The final category are those used for copulation, and deposition of the spermatozoa (sperm) within the male, these include the penis, urethra, vas deferens, and Cowper's gland.

Major secondary sexual characteristics includes: larger, more muscular stature, deepened voice, facial and body hair, broad shoulders, and development of an adam's apple. An important sexual hormone of males is androgen, and particularly testosterone.

The testes release a hormone that controls the development of sperm. This hormone is also responsible for the development of physical characteristics in men such as facial hair and a deep voice.

The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which leads from the vulva, the vaginal opening, to the uterus; the uterus, which holds the developing fetus; and the ovaries, which produce the female's ova. The breasts are involved during the parenting stage of reproduction, but in most classifications they are not considered to be part of the female reproductive system.

The vagina meets the outside at the vulva, which also includes the labia, clitoris and urethra; during intercourse this area is lubricated by mucus secreted by the Bartholin's glands. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. Each ovary contains hundreds of egg cells or ova (singular ovum).

Approximately every 28 days, the pituitary gland releases a hormone that stimulates some of the ova to develop and grow. One ovum is released and it passes through the fallopian tube into the uterus. Hormones produced by the ovaries prepare the uterus to receive the ovum. The lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through the process of menstruation. If the ovum is fertilized by sperm, it attaches to the endometrium and the fetus develops.

Most mammal reproductive systems are similar, however, there are some notable differences between the non-human mammals and humans. For instance, most male mammals have a penis which is stored internally until erect, and most have a penis bone or baculum. Additionally, males of most species do not remain continually sexually fertile as humans do. Like humans, most groups of mammals have descended testicles found within a scrotum, however, others have descended testicles that rest on the ventral body wall, and a few groups of mammals, such as elephants, have undescended testicles found deep within their body cavities near their kidneys.[5]

The reproductive system of marsupials is unique in that the female has two vaginae, both of which open externally through one orifice but lead to different compartments within the uterus; males usually have a two-pronged penis which corresponds to the females' two vaginae. Marsupials typically develop their offspring in an external pouch containing teats to which their newborn young (joeys) attach themselves for post uterine development. Also, marsupials have a unique prepenial scrotum.[6] The 15mm (5/8 in) long newborn joey instinctively crawls and wriggles the several inches (15cm), while clinging to fur, on the way to its mother's pouch.

The uterus and vagina are unique to mammals with no homologue in birds, reptiles, amphibians, or fish.[citation needed] In place of the uterus the other vertebrate groups have an unmodified oviduct leading directly to a cloaca, which is a shared exit-hole for gametes, urine, and feces. Monotremes (i.e. platypus and echidnas), a group of egg-laying mammals, also lack a uterus and vagina, and in that respect have a reproductive system resembling that of a reptile.

In domestic canines, sexual maturity (puberty) occurs between the ages of 6 to 12 months for both males and females, although this can be delayed until up to two years of age for some large breeds.

The mare's reproductive system is responsible for controlling gestation, birth, and lactation, as well as her estrous cycle and mating behavior. The stallion's reproductive system is responsible for his sexual behavior and secondary sex characteristics (such as a large crest).

Male and female birds have a cloaca, an opening through which eggs, sperm, and wastes pass. Intercourse is performed by pressing the lips of the cloacae together, which is sometimes knowna intromittent organ which is known as a phallus that is analogous to the mammals' penis. The female lays amniotic eggs in which the young fetus continues to develop after it leaves the female's body. Unlike most vertebrates female birds typically have only one functional ovary and oviduct.[7] As a group, birds, like mammals, are noted for their high level of parental care.

Reptiles are almost all sexually dimorphic, and exhibit internal fertilization through the cloaca. Some reptiles lay eggs while others are viviparous (animals that deliver live young). Reproductive organs are found within the cloaca of reptiles. Most male reptiles have copulatory organs, which are usually retracted or inverted and stored inside the body. In turtles and crocodilians, the male has a single median penis-like organ, while male snakes and lizards each possess a pair of penis-like organs.

Most amphibians exhibit external fertilization of eggs, typically within the water, though some amphibians such as caecilians have internal fertilization.[8] All have paired, internal gonads, connected by ducts to the cloaca.

Fish exhibit a wide range of different reproductive strategies. Most fish however are oviparous and exhibit external fertilization. In this process, females use their cloaca to release large quantities of their gametes, called spawn into the water and one or more males release "milt", a white fluid containing many sperm over the unfertilized eggs. Other species of fish are oviparous and have internal fertilization aided by pelvic or anal fins that are modified into an intromittent organ analogous to the human penis.[9] A small portion of fish species are either viviparous or ovoviviparous, and are collectively known as livebearers.[10]

Fish gonads are typically pairs of either ovaries or testes. Most fish are sexually dimorphic but some species are hermaphroditic or unisexual.[11]

Invertebrates have an extremely diverse array of reproductive systems, the only commonality may be that they all lay eggs. Also, aside from cephalopods, and arthropods, nearly all other invertebrates are hermaphroditic and exhibit external fertilization.

All cephalopods are sexually dimorphic and reproduce by laying eggs. Most cephalopods have semi-internal fertilization, in which the male places his gametes inside the female's mantle cavity or pallial cavity to fertilize the ova found in the female's single ovary.[12] Likewise, male cephalopods have only a single testicle. In the female of most cephalopods the nidamental glands aid in development of the egg.

The "penis" in most unshelled male cephalopods (Coleoidea) is a long and muscular end of the gonoduct used to transfer spermatophores to a modified arm called a hectocotylus. That in turn is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the "penis" is long and able to extend beyond the mantle cavity and transfer the spermatophores directly to the female.

Most insects reproduce oviparously, i.e. by laying eggs. The eggs are produced by the female in a pair of ovaries. Sperm, produced by the male in one testis or more commonly two, is transmitted to the female during mating by means of external genitalia. The sperm is stored within the female in one or more spermathecae. At the time of fertilization, the eggs travel along oviducts to be fertilized by the sperm and are then expelled from the body ("laid"), in most cases via an ovipositor.

Arachnids may have one or two gonads, which are located in the abdomen. The genital opening is usually located on the underside of the second abdominal segment. In most species, the male transfers sperm to the female in a package, or spermatophore. Complex courtship rituals have evolved in many arachnids to ensure the safe delivery of the sperm to the female.[13]

Arachnids usually lay yolky eggs, which hatch into immatures that resemble adults. Scorpions, however, are either ovoviviparous or viviparous, depending on species, and bear live young.

Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction.[14] Plants that are not flowering plants (green algae, mosses, liverworts, hornworts, ferns and gymnosperms such as conifers) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, and is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel (1793) studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions.

Fungal reproduction is complex, reflecting the differences in lifestyles and genetic makeup within this diverse kingdom of organisms.[15] It is estimated that a third of all fungi reproduce using more than one method of propagation; for example, reproduction may occur in two well-differentiated stages within the life cycle of a species, the teleomorph and the anamorph.[16] Environmental conditions trigger genetically determined developmental states that lead to the creation of specialized structures for sexual or asexual reproduction. These structures aid reproduction by efficiently dispersing spores or spore-containing propagules.

Excerpt from:
Reproductive system - Wikipedia


  1. Human Reproduction